The present invention relates to an electronic apparatus, and more specifically to an electronic apparatus with a combination of a solar battery and an information display means.
In the case in which a solar battery is used as a primary cell of an information display that includes an electronic watch, a solar battery module is often positioned at the watch face, in order to receive light for conversion to electrical energy.
That is, as shown in FIG. 3, a solar battery module 3, made up of a solar battery formed on a substrate, is disposed at the position of a watch face 4, this being used as the watch face as is. Light is converted to electrical energy and used to charge a secondary cell such as a nickel-cadmium battery, electrical energy from the secondary cell being extracted so as to drive the watch.
Another means, as shown in FIG. 4, is one in which a solar battery module 3 is disposed below the watch face 4. In either case, in a solar battery module that obtains an electromotive force obtained from four solar battery elements, the shape shown in FIG. 9 is usually used.
In the configuration of a solar battery shown in FIG. 9, as shown in FIG. 10, the electrodes 5 of the four solar batteries 6 are connected by using an extended electrode from part of the electrodes, electromotive force being extracted from output electrode 7 and 7xe2x80x2 provided at these ends.
In a solar battery 6 of the past, as shown in FIG. 19(A), solar battery 6 is formed by laminating, onto a transparent substrate 11, electrodes 12 and 14 and, for example, a P-I-N type amorphous silicon layer 13, wherein, because the electromotive force occurring during operation is limited to 0.5 V or so, for use as a power supply in an electronic watch, it is not possible with one element 6 to charge a secondary cell such as a nickel-cadmium battery.
Given the above, the structure adopted is one in which a plurality of solar batteries 6 are disposed on the substrate 11, these elements 6 being connected in series so that the electromotive forces thereof are added, thereby generating a voltage that charges a secondary battery.
FIG. 19(B) is a schematic representation of the connection structure of the solar battery 6. This solar battery 6 is formed by forming a transparent conductive film 12 onto a glass substrate 11, onto which is then formed a P-I-N type amorphous silicon film (hereinafter abbreviated a-Si film), and further onto which is formed a metal electrode film 14.
An electromotive force generated because of the light incident from below the substrate 11 can be extracted from the transparent conductive film 12 and the metal electrode film 14 that surround the a-Si film 13 on both sides.
The laminate structure on the top of the substrate 11 is divided between left and right at substantially the center in FIG. 19(B), and both sides thereof are other solar battery element regions, the left and right sides being called element A and element B, respectively, for the purpose of the description herein.
The metal electrode film 14 of the element A and the transparent electrode film 12 of the element B are linked, thereby connecting the solar battery elements 6 and 6xe2x80x2 in series.
At locations other than FIG. 19(B) as well, there is the same type of connection between the metal electrode film 14 and the transparent conductive film 12 of adjacent elements 6 and 6xe2x80x2, thereby making a series connection between a plurality of solar battery elements 6 and 6xe2x80x2 formed on the substrate 11, so as to form a solar battery with the desired electromotive force.
A method for manufacturing a solar battery such as noted above is described below, with reference to FIG. 19(A) and FIG. 19(B).
First, as shown in FIG. 19(A), a transparent conductive film 12 is formed on the substrate 11. This is, for example, an SnO2 film formed by a CVD process.
Then, laser machining is done of the SnO2 film so as to pattern it to the desired electrode shape. Next, a CVD process is used to laminate an a-Si film 13 onto the transparent conductive film 12, this being then laser machined to pattern the desired shape.
Additionally, a metal film that will serve as the metal electrode film 14 is sputtered onto the transparent conductive film 12 and the a-Si film 13, and the metal electrode film 14 is again laser machined to obtain the desired patterning shape for an electrode.
A solar cell such as shown in FIG. 9 or FIG. 10 having a connection cross-sectional structure as shown in FIG. 19(B) is completed in this manner. The cross-sectional construction other than the connection part is as shown in FIG. 19(A).
The relationship between the information display means of the past and a solar battery module including a solar battery 6 is one in which, with an opaque solar battery 6 of a special color, for example, it is difficult to use this at the surface of an information display means of an electronic apparatus including a watch face or liquid-crystal display of an electronic watch.
For example, the general approach is to form this integrally with the watch face, or to dispose it on the lower side of the watch face and, for that purpose, for example, in the case of a watch face, holes are appropriately formed in the watch face, so that sunlight can strike the solar battery 6, or the solar battery 6 itself is made a blackish color or other color that does not stand out, with the solar battery 6 itself being visible to the outside.
Another past example is, as shown in FIG. 11, one in which a solar battery 6 is annularly disposed around the periphery of the watch face.
In a watch configured as noted above, however, the watch becomes special and more costly, and is either limited in application or limited in the quantity that will be sold.
In the same manner, in an information display means other than a watch, such as an electronic apparatus in which a solar battery 6 drives a display means that uses a liquid crystal, it is impossible to dispose an opaque solar battery on the surface of the liquid-crystal display means, and difficult to form holes in the liquid-crystal display for the purpose of causing sunlight to pass therethrough.
Additionally, as a method to solve the above-noted technological problems, there has been a proposal for a watch or a liquid-crystal display in which a solar battery is formed linearly with a fine width on a transparent substrate, so that the solar battery is formed so as to cover the upper surface of a information display so as to be invisible to the human eye.
In the prior art, however, there was merely a vague indication of this configuration, and neither a technical basis nor disclosed data to indicate just what dimension would produce a desirable effect, the prior art, therefore, not going beyond the realm of an idea.
In a watch with a solar battery of the past as described above, in the case in which a solar battery module is disposed as the watch face, the presence of the solar battery module imposes restrictions with regard to watch face design.
Even if the solar battery module is disposed below the watch face, the watch face must have transparency to light, thereby being restricted with regard to materials and design, meaning that it is not possible to use a watch face with various materials and designed.
If it were possible to impart transparency to light to a solar battery module 3 formed by a solar battery 6 on a substrate, and also form the solar battery 6 so that it not visible to the human eye, it would be possible to use a solar battery module 3 formed by a solar battery 6 on a substrate on an information display such as a liquid-crystal display or watch face, or in a protective glass crystal, thereby enabling the fabrication of an electronic apparatus, such as a solar battery watch, without restrictions imposed with regard to design of the watch face or liquid-crystal display.
Additionally, if the configuration is made so that efficient opto-electromotive force is obtained with a solar battery formed as linear elements with even a finer width, it is possible not only to increase the amount of electricity generated, but also to make the solar battery smaller.
Accordingly, it is an object of the present invention to improve on the above-noted problems of the past, by providing an electronic apparatus with an information display means driven by a solar battery, wherein, a solar battery in the shape of a linear strip of fine width that cannot be seen by the human eye is formed on a transparent substrate and covers minimally a part of the surface of a prescribed information display.
In order to achieve the above-noted objects, the present invention has the following basic technical constitution. Specifically, an electronic apparatus with a solar battery according to the present invention is an electronic apparatus in which the major portion of an information display surface of an information display means is covered by a transparent substrate having a solar battery, wherein the solar battery is formed on the transparent substrate as a linear element of fine width so that the major transparent part of the transparent substrate is not blocked thereby, the solar battery being formed so that it protrudes minimally at one main surface of the transparent substrate, the transparent substrate having the solar battery being disposed on the side of the direction of light incidence with respect to the information display means, and the solar battery formed so as to protrude from the transparent substrate being formed so as to oppose the information display means on the transparent substrate.
That is, in a electronic apparatus according to the present invention, there is particular use of a side wall formed in the longitudinal direction of the solar battery to collect more incident light, thereby efficiently generating electricity, by making the configuration such that the solar battery protrudes from the upper surface of the transparent substrate.
Another aspect of the present invention is a solar battery module, in which a solar battery is formed on a surface of a transparent substrate, the solar battery being formed as a linear element of fine width, so that a major transparent part of the transparent substrate is not blocked thereby, the solar battery being formed so that it protrudes minimally at one main surface of the transparent substrate.
Yet another aspect of the present invention is a watch with a solar battery, in which the above-noted solar battery module is disposed on the watch face.